Birth Control and Breast Cancer: What’s the Link?

Certain hormones made naturally by the body can play a role in breast cancer development. But what about artificial (synthetic) hormones found in some forms of birth control like the pill, Depo-Provera injection, and intrauterine device (IUD)?

While research has pointed to a possible link between hormonal birth control use and a slight increase in breast cancer risk, experts say it's important to consider these findings in context.

This article provides an overview of research on hormonal birth control methods and breast cancer risk, hormonal birth control's potential protective benefits, and more.

Birth Control and Breast Cancer Risk: Split Opinions

For decades, researchers have been looking a connection between hormonal birth control and increased breast cancer risk, and the findings are a bit complex. 

Evidence shows the risk of breast cancer is slightly higher in people who use or have recently used come off of hormonal birth control. Additionally, the longer a person is exposed to the hormones can increase their potential breast cancer risk. The estimated risk percentage varies depending on the specific type of contraceptive. 

However, it's important to consider these findings in context. The overall risk for developing breast cancer in most hormonal birth control users is on the lower end to begin with—so a slightly increased risk may not have a significant impact in most cases. More studies are needed to include newer forms of birth control with lower doses of hormones than the older ones, however.

Breakdown of Research by Birth Control Type

Several different types of hormonal birth control methods have been researched concerning breast cancer risk, with birth control pills being the most closely studied. 

The Pill

Oral contraceptives (known as birth control pills or  “the pill”) come in two forms: a combination pill with estrogen and progesterone or a pill that includes progesterone only.

Research has shown that using combination birth control pills, or having used them recently, is linked to a slight increase in breast cancer risk. Some of the most notable studies have found:

• The risk of developing breast cancer may be 20% to 30% higher than in people who have never used them.
• The risk of developing breast cancer decreased once users stopped taking the pill, and in some cases, the risk went away entirely after roughly 10 years.

Findings on the progestin-only pill (also known as the minipill) and its relationship to breast cancer risk are less clear than those on the pill, and they've shown mixed results. Some studies have found a slight increase in the risk of breast cancer in minipill users, while others have found no connection.

IUD

Hormonal intrauterine devices (IUDs) have also been studied for breast cancer risk with mixed results.

Some studies have not found a notable link between breast cancer risk and the Mirena IUD (levonorgestresl-releaseing intrauterine system, made of progestin, a synthetic form of progesterone), while others noted a potential 20% increase in breast cancer risk in Mirena users.

Depo-Provera

Not enough research has been done on the link between Depo-Provera (medroxyprogesterone, an injectable progestin known as the Depo shot or birth control shot) and breast cancer risk. 

Most studies have found no risk of breast cancer in users of Depo-Provera. However, some findings show a possible increased breast cancer risk in long-term users of the Depo shot when compared to people who do not have a history of using this type of birth control.

Implant

Research is also lacking into the progestin-only contraceptive Nexplanon, an implant placed under the skin in the upper arm. In studies that have included this type of contraceptive, results show minimal to nonexistent risk.

Birth Control Patch

Birth control patches Xulane and Twirla (estrogen and different types of progestin) have been included in a few studies on this topic. Results show that any increased breast cancer risk for this form of hormonal birth control is not statistically significant.

Vaginal Ring

Similarly, the vaginal ring (NuvaRing) is made of two types of synthetic estrogens and didn’t appear to be linked to an increased breast cancer risk.

Possible Benefits for Other Types of Cancer

Evidence shows that certain types of hormonal birth control may help prevent other types of cancer. When compared to people who have not used hormonal birth controls pills, they may:

• Lower the risk of ovarian cancer
• Lower the risk of endometrial cancer
• Lower the risk of colorectal cancer

This protection factor may last for decades after a person stops taking the pill, as well.

Nonhormonal Birth Control Alternatives

Some people prefer not to use hormonal birth control. Several nonhormonal alternatives include:

• Nonhormonal IUD (Paragard): Releases a tiny amount of copper to make the uterus environment toxic to sperm and eggs
  
• Phexxi: A gel inserted into the vagina changes its pH balance, making it difficult for sperm to reach an egg
• Cervical cap: A small piece of silicon that covers the entrance to the cervix and prevents sperm from reaching the egg
• The sponge: A polyurethane foam device that blocks the entrance to the cervix and contains spermicide to kill sperm
• A diaphragm: A plastic cap covering the cervix that prevents sperm from making contact with an egg
• Spermicide: A cream or gel inserted into the vagina that slows down sperm, making it harder for them to reach the egg (most effective when used with condoms, diaphragms, sponges, and other types of contraceptives)
• Condoms: Worn externally (on the penis) or internally (inserted into the vagina or anus), providing a physical barrier between sexual partners

Summary

Studies have found that some hormonal birth control may slightly increase the risk of breast cancer. Other data show that risk remains relatively low for most birth control users. Because each person's breast cancer risk is unique and dependent on multiple factors, experts suggest weighing the potential risks and benefits with a healthcare provider to decide on the best option for you.

A Word From Verywell

Breast cancer is among the most common cancers faced by female adults in the United States, so it's important to be aware of your risk and your family history of the disease. Knowing your risk will help you decide whether to use hormonal birth control and which method is the safest and best for you.